Winter
by MidnytLove
Summary: Reports of increasing activity in Hueco Mundo had the Gotei Thirteen baffled. Captain Hitsugaya was sent to investigate but what will he find? What will happen to our Captain if he found himself in a different world?
1. Journey

Endless night shrouded Hueco Mundo when a single young man exited the senkaimon. His slightly longer, spikey white hair rustled gently in the wind as the door closed and disappeared behind him. Sharp turquoise eyes scanned the expansive dunes for life. He sensed a few small Hollows off to his right but they were too scared to come outright.

"That's where I need to go," he muttered when he spotted what he was looking for in the distance. The infamous palace beneath the crescent moon lay in ruins from the winter war three years ago. He still remembers that war as if it were yesterday. The war that made him almost murder his best friend in cold blood. Aizen has been captured and is paying for his crimes but after all that death and destruction...  
Executing him slowly and painfully will still be far too merciful.

Many things have changed in the past three years. The missing Captain positions were quickly filled by invitation from the Head Captain. Even though the new Captains have been pardoned for their past crimes, he still hates the idea of a certain blonde visorde being around the only other person he cares about.

With the loss of his arm, Head Captain Yamamoto stepped down to give reign to a younger, more open-minded Captain. He believed his successor will steer Soul Society in a more understanding direction, instead of his own steadfast traditional ways. Shunsui Kyoraku accepted his new title reluctantly but being one of Yamamoto's original two students, he knew he would make his master proud.

The new Head Captain and Gotei Thirteen have made it their mission to hunt down all the remaining Arrancars and Vasto Lordes in Hueco Mundo. It has been going quite well. But lately, several reports have been coming in about unusual spikes of energy from the palace ruins. None was sent to investigate... Until now.

"Cap-tain," The voluptuous Matsumoto almost sang as she ran up the white dune beside her young superior. Seven officers and a handful of unseated members of squad ten joined her beside their Captain.

"You're late," the young Captain huffed and threw the edge of his dark green scarf over his shoulder.

"Awww! Captain, do you know how exhausting it is to run after all that paperwork?" she whined playfully.

"Maybe if you do more actual work instead of drinking, you won't be so out of shape," one slender eyebrow twitched with annoyance as he adjusted the new chain that held Hyourinmaru in place.

She gasped loudly, "Are you calling me fa-?!"

"Captain Hitsugaya!" A small, dark haired figure landed out of her flash step with several more officers.

"Rukia Kuchiki," Hitsugaya greeted, welcoming the interruption.

"Captain Ukitake sends his apologies. He won't be joining us today," she informed him with a sad smile. "He's been feeling under the weather for the past week."

"It's quite alright. I believe congratulations are in order for your official promotion," he nodded towards her Lieutenant's badge as he eyed several of her officers with a stern look. They looked a little nervous under his gaze and stood a little straighter behind their Lieutenant.

"Thank you, sir," she bowed as her smile grew wider. "This is my first official mission as Lieutenant."

"I am sure you will lead your men well. Now, to business," Hitsugaya stepped forward. He eyed the ruins one more time before turning fully to the group gathered. "Everyone here has been briefed about the strange occurrences at the ruins of Las Noches. We are here to seek out the source and investigate. If it is an immediate danger to Soul Society or the world of the Living, we must not hesitate to eliminate it. Be alert and hide your spirit energy as much as possible."

"Permission to speak, Sir?" An unseated member raised his hand cautiously.

"Granted," the young Captain watched his concerned face.

"What is the worst thing we can expect in there?" Most of the other members' ears perked up at the question.

"It can either be Arrancars or Vasto Lordes but hopefully it's just some small fry messing around. Though, if my suspicions are correct..." He trailed off deep in thought then turned. "Expect the worst in there. Be at your full power at all times when encountering an enemy," Hitsugaya's eyes swept over the people in front of him. A bad feeling started to creep into his heart and it took no effort to keep it from surfacing.

"Why? What can be worse, Captain?" An officer of squad thirteen grew worried.

The young captain turned his back, "Espada." He let it sink in for a few seconds, "Move out!"

"Yes, sir!" Both squads cheered and followed the Squad Ten Captain to the palace.

Halfway to their destination Matsumoto decided to get some answers. He hasn't raised this issue at all before leaving. If she had known the risks, she would have never brought unseated members. "Captain... I thought all the Espada were destroyed in the war."

"No, some weren't. A few of them survived but where they have gone however… is uncertain."

"Which ones?" Matsumoto tried to remember.

"The blue haired Espade that almost killed Kuchiki and Kurosaki. I believe his rank was number six," Hitsugaya peered at Rukia from the corner of his eye.

Rukia gasped, "Grimmjow? He's still alive? I thought Ichigo defeated him."

"No, Captain Kurotsuchi confirmed his status and is monitoring him as far as my knowledge stretches," he dodged around of the crystal tree. "Then there is the one I fought. She was ranked number three," he felt a pang of anger for letting her get away.

Matsumoto kept silent when she felt his spirit energy fluctuated a bit but was hidden again just as quickly. She fell behind to run besides Rukia once more.

"What is wrong with the Captain?" Rukia asked her when Matsumoto was within earshot.

"Just reminiscing, I guess," the blonde shrugged.

"I know the feeling. I mean, the last time I was here, was to save Orihime," Rukia looked towards their destination with disgust.

Hitsugaya suddenly skidded to a stop. The entire group came to such a screaming halt, the unseated members almost ran into each other.

"Captain?" Matsumoto stopped beside her superior. He watched him close his eyes. His breathing became ragged. She has never seen him like this before.

Rukia came up behind Matsumoto, "He's probably talking to Hyourinmaru."

Matsumoto only nodded without reverting her gaze anywhere else. She felt the temperature drop around him sharply. What was going on?

"It's a dragon!" The Captain's eyes snapped open. His turquoise eyes glowed with his spirit energy.

"A dragon?" Rukia asked watching her men in her peripheral vision. Some gasped in awe, others in terror.

"Yes. There is no mistaking it. Lieutenant Kuchiki, take your men and the rest of my squad back to Soul Society. It already knows we're here. I trust Hyourinmaru is correct about this situation. This is not a Hollow or even Espada we're dealing with here," Hitsugaya concluded. The old would in his side pulsated at the memory…

"Sir, I earned my Bankai. Let me fight!" Rukia pleaded.

"Are you disobeying my direct order?" Hitsugaya glared at her.

"N-no, sir," Rukia begrudgingly turned as the rest of the group followed her. Some murmuring and stared at the Captain and Lieutenant of Squad ten. The senkaimon opening ahead of her.

"Rangiku... Go with them," Hitsugaya spoke in a barely audible voice. Matsumoto looked at him with baffled eyes at the use of her first name. She tried to read him but his longer hair shrouded his eyes.

"What? With all due respect, sir… No!" Matsumoto was so perplexed that he would even suggest it. "It's the duty of a Lieutenant to protect her Captain, remember? No matter the cost."

Hitsugaya scoffed lowly, "Why is that when someone says 'With all due respect', they really mean 'Kiss my ass'?" He finally looked at his Lieutenant, her blue eyes widened when she heard him. He sighed. "No. I need you to deliver this message to Head Captain Kyouraku," as he finished, a hell butterfly materialised on his fingertip.

He relayed the message and the small black being floated into Matsumoto's awaiting hands. Matsumoto looked at the butterfly, then back to her Captain. "Be careful," she gave a nod and entered the open gate behind the small group.

Hitsugaya kept watching her silently until the door closed and disappeared. "No promises," he whispered then turned and unsheathed Hyourinmaru. He breathed in the reishi rich air as the wind swirling around him slowly start to pick up.

The blade in his hand reverberated in anticipation of a glorious battle. With the sound of a roar echoing in his ears, he pointed his blade towards the sky and shouted, "Bankai! Diaguren Hyourinmaru!"

Magnificent wings of ice sprouted from the Captain's back as an icy tail whipped into place. The legendary serpentine dragon roared as it emerged from the tip of its master's blade.

"So we meet again... demon," was the only thing the young Captain said before he launched into the air with a flap of his wings.

Las Noches was approaching quickly as both master and blade prepared themselves for their foe. Old memories of their last battle stirred in the back of his mind. The red eyes of his dragon glinting with the same memories. This time they will surely be ready for it...


	2. A year ago

The blade in his hand reverberated in anticipation of a glorious battle. With the sound of a roar echoing in his ears, he pointed his blade towards the sky and shouted, "Bankai! Diaguren Hyourinmaru!"

Magnificent wings of ice sprouted from the Captain's back as an icy tail whipped into place. The legendary serpentine dragon roared as it emerged from the tip of its master's blade.

"So we meet again... demon," was the only thing the young Captain said before he launched into the air with a flap of his wings.

Las Noches was approaching quickly as both master and blade prepared themselves for their foe. Old memories of their last battle stirred in the back of his mind. The red eyes of his dragon glinted with the same memories. This time they will surely be ready for it...

 **xXx**

 **1 Year Ago...**

It was a bright winter's day. The sky was once again clear of all the dark clouds after weeks of constant snow. A large explosion of icy wind blasted through a cave opening not too far from the Squad Ten barracks. Every Shinigami in the immediate area stood in silence as they listened. They knew it was Captain Hitsugaya, training to fully master his Bankai. Today however... Training was different. They all felt a significant drop in his powerful spirit energy. All of the squad ten members got a tinge of worry. In all his training the last two years, never did they feel his spirit energy drop this low before.

"Shouldn't someone go check up on the Captain?" The question escaped from a new female recruit within a group.

"Don't worry about our Captain," a delicate female voice reassured her from the side.

"Lieutenant Matsumoto!" The lower members acknowledged her bowed in greeting. The blonde simply nodded and walked past them to stare in the direction of the cave.

"Like I said, don't worry about our Captain. He may be the youngest Captain in Soul Society history but... I strongly believe he will soon be the greatest Captain that will ever live," she turned to the recruits. Her eyes shown with so much warmth and faith, it was almost tangible. The rest of the squad's worries vanished instantly.

"Now, we should follow our Captain's example. Back to training," she ordered and watched them leave to their respective training grounds. Once their backs were turned, her eyes turned sad as she looked back in the direction of the cave. "Why do you keep doing this to yourself?" She whispered in question. A flash of her best friend lifeless on a slab came to mind. She wasn't fast or strong enough to save Gin but in the end, he was willing to die for her. "Please don't you leave, too," she sighed and left to find her drinking partners.

 **xXx**

Captain Hitsugaya plunged his blade into the ground of his cave as he fought to steady his breathing. Both hands white knuckled over the hilt. Legs grew numb and gave way as he sank lower to his knees. Ice wings limp at his sides.

 _"Are you alright, master?"_ A majestic head lowered to look at his master eye to eye. Only the Captain's heavy gasps broke the silence _. "Why did you exert yourself so much today?"_ Hyourinmaru watched faint white veins crack his master's wings.

"I-I'm fine, Hyourinmaru," he stuttered between breaths and stood with great effort, ignoring the second question. The Captain's legs gave way again. The Great Spirit dove forward and caught him on his snout. Hitsugaya gasped in surprise. He should be able to handle this but gave in and just leaned on him anyway. For an instant, his eyes grew distant.

 _"What's on your mind, master?"_ Hyourinmaru almost purred to cover the concern in his voice.

Hitsugaya's eyes blinked back to reality, "What kind of question is that? You know very well what's on my mind. You're still a part of me, are you not?" He snapped with frustration. Hyourinmaru flinched slightly at the retort. A shattering crack of ice disturbed the awkward silence. Hitsugaya turned his head to see his tail shatter onto the cave floor.

" _Tell me anyway,"_ Hyourinmaru darted his gaze to the final petal of the remaining flower. Almost completely gone.

"I was only wondering... if I will ever master yo- our Bankai," Hitsugaya sighed as he changed his wording and placed a shaky hand on the beast's head.

 _"Of that I am certain, master,"_ Hyourinmaru let out a low purr-like growl as his crimson eyes brightened. _"But I will not make it easy,"_ Hyourinmaru gave a throaty chuckle.

"I don't expect you to," Hitsugaya smiled.

 _"When we reach that point however, we won't need those any longer,"_ Hyourinmaru motioned his head to the disappearing petal.

"Now that is something to look forward to," the Captain looked up at the remaining fragments. A small wave of relief washed over him at the revelation.

 _"Master... You should rest. We both went through enough today,"_ Hyourinmaru pulled back slowly as the Captain stood wearily on his own. The icy beast spread his own cracked wings to emphasize. Hitsugaya only nodded and undid his Bankai. The great serpentine dragon before him disappeared slowly and the remaining ice on his body evaporated.

"Thank you, my friend," Hitsugaya shakily walked to the entrance where he left his belongings. His eyes roamed the white silk of his haori. A sense of guilt reminded him why he was working so hard. He quickly pushed it aside and slipped his arm through it soundlessly, then tightened the thin chain that held Hyourinmaru to his back. A satisfied roar echoed through the Captain's head when the blade was sheathed into place. Hitsugaya folded his arms, taking in a lungful of icy air. His shoulders relaxed as he stepped outside. The day was certainly bright, he thought shading his eyes from the light. He went through all the training mentally, remembering how something changed with Hyourinmaru but he couldn't quite put his finger on it. He was halfway back to the barracks, deep in thought when he heard it...

Cries for help echoed through the Rukongai. Hundreds of souls scattered in different directions. Warily, Hitsugaya flash stepped towards the fleeing souls to find the cause. Turquoise eyes roamed the area as he flashed over roofs. Smoke obscured most of the district from view but an ominous presence permeated in the distance.

An elderly man caught Hitsugaya by the sleeve of his shihakusho when he landed to catch his breath, "Are you a Captain? Please! You have to help us!" His tone so distressed, it shook his whole body.

"What is it?" Hitsugaya held the man upright. His own limbs started trembling from fatigue.

"I don't know what it is. All I know is that it's monstrous... and has house-sized wings!" The man fell to his knees. "Please Captain. Help us!"

"Where?"

The man pointed in a direction that made Hitsugaya's heart sank through his feet. "Junrinan," the man answered. Hyourinmaru's ear-splitting roar vibrated the blade in its sheath.

"Grandma," with a flash, the Captain disappeared. His legs burned in protest but it was soon forgotten as new determination flooded his limbs. "For so many souls to run, I have to give it everything I have."

 _"Master! Please be reasonable! You have already used too much of your spirit energy. Don't be foolish!"_ Hyourinmaru's voice rang with despair _. "Wait for reinforcements."_

"If what that man said is true, we cannot wait!" The Captain ignored the blade's pleas and commanded, "Give me everything you have Hyourinmaru!"

A few moments of silence came and gone before a low voice answered, _"Very well... Master."_

Renewing waves of energy filled the Captain's limbs as he pressed forward. Navigating through the labyrinth of streets and souls, he made way towards one destination. He skid to a halt at the side of an immense crater. A vast ditch dragged for several meters that led through a half crushed house. Hitsugaya's body grew numb when he recognised the broken walls, "No! Grandma!" He flashed through the broken door. Eyes searching. Spirit sensing.

"To-shiro?" A faint voice called from under nearby debris.

"Grandma," Hitsugaya strained and lifted the shattered beams from her chest. "A-are you alright?" he asked softly as he knelt at her side, gently helping her sit up.

"I- I think so," she coughed. Her breath coming in short gasps.

"What happened here?" he watched her carefully. Her face was far too pale for his liking. Bruises formed quickly on her wrinkled skin. Cuts trickling small streams of red from her neck and arms. Greying hair caked thick with blood at her right temple.

"I don't know, dear," she shook her head, wincing at the action. Hitsugaya iced his hand and held it to the wound on her head. She hissed at the touch but stilled for a few moments. "I do remember… hearing something," she paused, taking a moment to catch her breath. "It almost sound like…" she gasped at her own revelation.

"Sounded like what?" He pulled back.

"It almost sounded like your Hyourinmaru," her usual gentle features turned to outright terror.

"That can't be," Turquoise eyes grew wide. They both knew what that meant.

"You must go now," she took his free hand in hers when she saw him hesitate to leave her side. Trying to reassure him, she gave a small smile. "I will be alright now. Go do what you do best. Save them."

He quickly formed a small block of ice that he gently placed against her bleeding temple. Her frail hands held it in place when he stood, reluctant to leave her. Walking through what remained of the ruined house, he looked back at her. She smiled warmly at him.

"I will be back soon," he vanished.

"Please be careful, my dear," she sighed and watched a small dust cloud settled in the absence of the young Captain.

Hundreds of screaming souls still fled the area. Sharp eyes searched for the whereabouts of the creature. Thick smoke breached the trees not too far from where the trail of destruction ended. "We must be close n-" A screeching roar echoed through the district. Colossal wings blocked out the sun as the creature took to the air. Blackened claws glistened with blood. Decaying flesh and ripped wings painted horrors on the clear sky.

Hyourinmaru roared at the sight of their foe _. "A dragon? Here? How?"_ It was monstrous. Four twisted horns rose from its head like a crown. Its teeth bared and face gnarled as if it has seen a thousand battles. Protruding broken bones over nearly every inch of its spine only adding to the horrible sight.

"I guess we will find out," Hitsugaya unsheathed his blade. "Reign over the frosted Heavens, Hyourinmaru!" Dark clouds gathered overhead and the temperature began dropping. The Captain slashed his blade through the air multiple times as ice dragons formed with each swing.

The dark dragon roared again with an otherworldly screech. Eyes burning bright red when it spotted the attack. Ears rang and his head felt as if it was about to explode. Most of the ice dragons veered off course, disorientated by the sound, smashing and freezing anything in their path. The Captain shook the dazing sound out of his head.

 _"Please, Master!"_ Hyourinmaru's voice begged again, heavy with concern.

Hitsugaya shook his head clear and gripped the hilt tighter in an attempt to cut off his companion's continued pleas. "We cannot stop. We have its attention now," Hyourinmaru kept silent as the young Captain watched the dragon hover over them. The massive shadow loomed darkly over its new targets. With a swift beat of its wings, it dove head first into a set of houses right behind the Captain. Planks and tiles shattered into clouds of dust. Screams echoed through the district as a mouthful of souls were slung into the air. Blackened teeth opened to the gaping maw, ready to devour its meal when it was suddenly whiplashed to the side. A single silver chain locking its jaws shut. Red eyes followed the chains to home in on its captor. It's escaping meal forgotten…

A low growl rumbled through the land when red eyes dared the Captain to take another meal. Tattered wings spread and the earth quaked when claws dug into the ground. Wind surged around the beast and sucked Hitsugaya closer with each wing beat. The chains fell free and blackened teeth opened, ready to devour him.

 ** _"MASTER!"_** A ground trembling roar flew overhead.

"NO!" Hitsugaya protested when one of two remaining serpentines took his place. Hyourinmaru roared in agony. The Captain's chest tightened suddenly. "Hyourinmaru? Wh-what's happening?" The Captain's breath came up shorter as he watched the serpentine crack within the jaws of the black beast. Confusion struck him as he saw the blue body cracked but not freeze any bit of the beast's face as expected. Instead, blue slowly turned red. The remaining serpentine fell and writhed on the ground as if it was burning from the inside out. Hitsugaya ignored his own pain slowly spreading in his chest and ran to its aide when a pained filled roar echoed through the district. Turquoise eyes snapped back to the black beast's jaws. Blue almost completely gone.

 _"G-get away!"_ The serpentine on the ground flapped his wings with great effort as it shot straight up, almost knocking back his master. It hovered there a few moments before plunging straight back down. Just before it hit the ground it turned and rammed itself into the black beast's head encasing it in ice partway. The beast's top right horn snapped off from the impact. It bounced from force until it embedded itself within a shattered tree. The black dragon roared in anger at the loss of its horn and dropped the serpentine from its jaws. Claws dug at the ice encasing the side of its head and neck.

The Captain, almost completely drained from his remaining spirit energy, sagged to his knees. He could only watch as the red serpentine shattered at the beast's feet. Lifeless.

Whispers… Soft singing touched the back of the Captain's mind. A song, unfamiliar to him. A song asking him, coaxing him to immerse himself within its song. It was tempting... Tempting like a bed for the weary man, drawing him closer.

Panicked eyes shook free from its bewitching song and roamed the motionless red body. It almost looked like it was glowing. Small clouds of red electricity floated and plumed around the terror filled face of the red Hyourinmaru. Slowly, wisps of fear and hate radiated from it in equal measure.

"What did it do to you?" Hitsugaya felt Hyourinmaru grow slightly faint. His own eyes heavy and threatening to slip shut.

 _"I-it injected me with some form of…"_ Hyourinmaru struggled to find the right word. His voice sounded strained when he continued, _"…dark magic?"_

"Like forbidden kido?"

 _"No,"_ Hyourinmaru paused to think but came up with nothing to compare it to. _"Whatever it is, it's not good. For either of us. Get ready master."_

Hitsugaya nodded and stood again. He heard the strain in his blade's voice. It was never this hard before but he knew it was his fault. If only he had not pushed himself so far earlier, he would have been more prepared now. If only he knew. Turquoise eyes watched the last of the ice fall from the beast's neck.

Turquoise locked with red, the whispers of the red song pushed back. Steel rose in defiance of black jaws. Beast and prey dared each other silently.

The alarms sounded within the Seireitei. The ground trembled at the sound. Claws dug deep as it shot forward. Roars and a howling screams rang through the sky. Then all was silent…

Moments of black passed by. Sharp pain ripped through his sleep constantly. He groaned and tried to lift a heavy hand to feel what happened. Final remnants of energy left him completely defenseless.

A faintly familiar feeling approached. There were no malicious intent but, he was simply just too tired to care about everything. "Captain!" An echo of a female voice wisped by his ear. The light around her head was blinding. It was like a golden halo untouched by the blackness flooding his vision.

Hitsugaya felt himself floating high. He tried to make sense of it all when his head rolled to the side. Half lidded eyes looked back to his battleground and only saw a faint green speck vanish with a flash when unconsciousness finally claimed him fully.

 **xXx**

A poorly lit cavern was suddenly filled with green. The veil tore with a shearing rip as the dark dragon fell from the rift. The fade green light revealing a haphazard wound stretching from its gnarled snout, over its head to halfway down its neck. Decaying blood and muck splashed onto the ground unceremoniously. Red eyes searched around the dark cavern as the rift closed behind it with a loud pop. Low, painful rumbles echoed off the walls.

"Now what have you done?" A towering male figure strode forward, its tone casual. It stood in front of the beast, watching, waiting for an answer. When none came, clawed fingers dug apprehensively into the wound with one swift swing. The dragon winced at the action but did not protest. "Ah. I see," he pulled back, only to drag the blood soaked fingers across gnarled lips of his own. Intrigue filled dark brown eyes when he dipped low to rip something from the beast's maw.

Shredded white silk trimmed with green was covered with fresh blood. "This smell… It almost smells like the Fade!" The figure exclaimed. "Tell me… Have you done it?"

The dragon almost purred as a wicked grin spread across his face.

"Well done, my pet," the figure walked towards an edge overlooking a deep trench. Red light emanated brightly beneath him. "The plan is on the verge of fruition and then no one will stop us. Stop me," The figure chuckled darkly.

The dragon lifted his still bleeding head. Red eyes searched for some relief from his master.

"Now for your reward," the figure raised his arms. Just below the edge, red crystals shattered loudly as it broke off like glass. The figure swung his arms towards the dragon in wide arches. The crystals followed silently and embedded itself within the dragon's neck. The dragon roared in agony as the crystals dug deeper to form jagged armour on both sides of its neck. The beast's head fell forward to catch its breath. The figure crouched in front of its snout.

"Excellent. Your conversion is almost complete. Be grateful you are the only true servant of the impending god," the figured touched the wound on the dragon's snout. Red energy poured from his hands to close the wound over its head. "Do not fail me," Red eyes became clear, heeding the threat.

The figure stood as he walked deeper into the cavern, "The last of the puppets are on their way. Desperate and greedy. It is only a matter of time before they too, will submit to my will," A low growl sounded in agreement when brown eyes flashed red in the darkness.

* * *

I just want to thank all the follows so far and the reviews.

I had this chapter done what feels like lifetime ago. Also, this is me waiting to have more chapters done before I post.

I have also posted this story on Ao3 under the same username if you want to follow me there~

Please review or leave a comment to what you think?

Thanks for reading~


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